The present invention relates in general to creel systems used in connection with yarn warping operations having tension control and protective features incorporated therein, and more particularly to apparatus and method for providing tension control, yarn motion sensing and yarn cutting responsive to over tension conditions in "V" type creels and the like, providing protection from tangled yarn packages and allowing rapid thread up operator convenience.
Creels of many configurations have been used in holding yarn packages during a warping operation. One typical form of creel which has been used in warping operations is the type known in the textile industry as a "V" creel. This name relates to its "V" shape when viewed from above with the warper being located a short distance from the point or apex of the "V", and the yarn is supplied to the warper from locations lying in a substantially vertical plane along the outside of the legs of the "V". The yarn packages are typically arranged in vertical columns of packages supported by a framework such that along each leg of the "V", one set of vertical columns of packages lying in a substantially vertical plane forming an outer or exterior working or running set while another similar number of packages arranged in plural vertical columns lie in a plane spaced inwardly and parallel to the outer set along each leg forming an interior reserve set of packages. These typically are mounted on chain systems or the like to facilitate interchanging the positions of the working or outer set and the interior or reload set.
One of the purposes of the "V" type creel is to facilitate rapid change over of the yarn packages from depleted to full ones by loading full packages on the interior set associated with each leg of the "V" on suitable skewers and, at the time of change over, substituting these fully loaded skewers transported by means of conveyor chains or swing gates or truck tracks to the outer working or running position. The depleted packages are rapidly transported to the reload or interior location, for replacement of the depleted packages. Because yarn packages can be changed en masse, in the "V" type creel, the facility to vary the size of yarn or the number of ends is enhanced, and thus the "V" creel is very useful where flexibility and variety are needed.
Prior to the advent of the present invention, the "V" creel has been beset by a number of deficiencies. Foremost is the difficulty of providing means to control the tension of the yarn arriving at the warper regardless of the yarn speed or distance travelled through the atmosphere and at the same time to provide rapid group threading of the creel and tensioning means.
Typically, the previous method of providing tension on a typical "V" creel system has been to use simple hooks or wires to wrap the yarn around on its way to the warper. Tension is caused by the angle of wrap, the balloon tension as the yarn leaves the package, the distance to the warper, and the instantaneous yarn speed. The prior methods employed with "V" creels provided an unknown and extremely variable tension and was essentially uncontrollable. In order to prevent tension extremes from causing the yarn to tangle, a secondary method using yarn clamps or zig-zag snubber bars was frequently provided in the yarn path and temporarily brought into and out of use when there was danger of tangling, such as during low speed and stop conditions. This secondary type of tension override made the tension of the yarn reaching the warper even more erratic and degraded the quality of the warp and eventual fabric made from it.
Another deficiency of the prior method of "V" creel operation using the hooks or wires to cause the tension effects to serve as a broken yarn detector and stop motion for the warper was that the wires or hooks were typically hinged so that when the yarn was in position and with some minimum tension, the stop motion was held off and the warper was allowed to continue running. If the yarn broke or lost tension, the wire pivoted around and broke an electrical contact to stop the warper. This technique was very common, but well known for its propensity to collect lint or entangle yarn and fail to operate.
An object of the present invention is the provision of a novel apparatus and method for achieving tension control, sensing of yarn motion, and tangled yarn defect protection in yarn creel systems for warping operations, particularly for "V" type creels, wherein means are provided to facilitate group threadup in a manner avoiding many difficulties and inconveniences characteristic of prior systems.
Another object of the present invention is the provision of a novel apparatus and method of providing tension control for "V" and similar type creels having tension control devices of a type generally similar to those disclosed in earlier U.S. Pat. No. 4,313,578, wherein a yarn motion sensor is included in the system whereby yarn leaving the package that stops moving will cause the warper to stop in a manner which is not dependent upon tension effects and is further protected against fuzz, lint and entangled yarn.
Yet another object of the present invention is the provision, in connection with yarn tension control apparatus for "V" creels and the like, of an automatic and controllable device at a location near each yarn package such that if a yarn package becomes entangled and the yarn feed off is impeded, causing an imminent breakage, a sacrificial cut of the yarn is made automatically at a position close to the supply package to allow time for the stopmotion to stop the mass of the warper before the cut end is wrapped into and perhaps lost in the warp. If the yarn end were allowed to break, particularly at a location close to the warper, the end frequently is lost into the warp, creating a considerable quality problem.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.